This invention relates to heat releasable indicia and to a method for transferring such heat releasable indicia from a carrier sheet to a receiving surface.
Pressure-sensitive numbering and lettering systems frequently found in the industrial lettering arts have been devised wherein an individual letter or number having a back surface coated with a high grip adhesive is individually sandwiched between a backing sheet coated with an adhesive repellant substance and a cover sheet having one side coated with a low grip adhesive substance and an opposite side containing a registered aligning form for cooperation with a guide line on a mounting surface, such as suggested in the U.S. Pat. No. 3,484,972 to R. E. Christman. While such systems have been designed for various surfaces such as windows, doors, walls, mirrors, automobile and truck paneling, et cetera, they are not believed to be extremely compatible with flexible surfaces such as fabrics which are subjected to extreme moisture and heat conditions such as occurring during normal fabric washing.
Heat transfers have been widely used in the application of indicia such as designs, pictures, letters, numbers, words, figures, marks or the like to a receiving surface and particularly in situations where the indicia is permanently bonded to a T-shirt or other fabric. Such heat transfers generally include an individual carrier sheet containing an individual design or other indicia and may include an intervening conventional release coating. The designs or other indicia are generally formed of an adhesive ink which includes a resinous plastisol, heat and light stabilizers, colorants, thickeners, thinners, or other materials which alter the physical ink properties. When applied to a receiving fabric surface, the carrier sheet and retained indicia are placed in direct immediate contact with the fabric surface while heat, such as supplied by an iron or the like, is applied to the oppositely disposed side of the carrier paper. The application of heat to the indicia partially or completely liquifies the resinous ink which engages the fabric fibers. After heating, the heat transfer is cooled thereby curing the resinous ink. The hardening of the resinous ink through cooling forms a permanent bond between the indicia and fabric surface which is greater than the previous or existent bond between the indicia and carrier sheet which thereby allows the carrier sheet to be peeled away leaving the cured indicia in permanent bond with the receiving fabric surface.
Separate individual heat transfers containing individual indicia which are to be used in conjunction with other such heat transfers poses problems of alignment and spacing when applied to a fabric surface and further problems may arise concerning handling and storage where a large multiplicity of varied indicia are involved.